Polymer Metal Research Articles

Effect of solution chemistry on the sedimentation, dissolution, and aggregation of the bimetallic Fe/Cu nanoparticles pre- and post-grafted with carboxymethyl cellulose

The suitability of iron-based nanomaterials or composites for in-situ remediation hinges on their physicochemical stability. Introducing surface modifications like metal doping or polymer grafting can regulate interparticle forces, influencing particle stability. Thus, probing how grafting methods (i.e., pre- or post-grafting) tune material properties controlling interparticle forces, comprehend the synergistic effect of metal doping and polymer grafting, and evaluate stability under varying geochemical conditions are the way forward in designing sustainable remediation strategies. To this end, time-dependent sedimentation, dissolution, and aggregation of four synthesized iron-based nanoparticles (bare iron (Fe), copper doped bimetallic iron/copper (Fe/Cu), pre- and post-grafted Fe/Cu with carboxymethyl cellulose (CMC) – CMCpre-Fe/Cu and CMCpost-Fe/Cu, respectively) were carried out as a function of solution chemistry (i.e., pH – 5 to 10, ionic strength, IS – 0 to 100 mM NaCl, initial particle concentration, C0–20 to 200 mg.L−1) mimicking geoenvironmental conditions. CMCpre-Fe/Cu exhibited markedly higher particle availability (> 91 %) against sedimentation than others (bare Fe/Cu (11.28 %) > bare Fe (7.33 %) > CMCpost-Fe/Cu (6.09 %)) – suggesting the pivotal role of grafting method on particle stability. XDLVO energy profiles revealed pre-grafting altered magnetic properties favoring surface charge-driven electrostatic repulsion over magnetic attraction, thereby limiting aggregation-induced particle settling. In contrast, superior magnetic force overrides the electrostatic behavior for bare and post-grafted particles. Unlike bare and post-grafted nanoparticles, CMCpre-Fe/Cu aggregate size correlated positively with [H+] and IS, consistent with their settling behavior. Rise in C0 showed a visible negative effect on particle aggregation and, thereby, sedimentation except for CMCpre-Fe/Cu by facilitating particle collision through Brownian movement. Both acidic pH and copper doping promoted nanoparticle dissolution, whereas pre-grafting can provide a plausible solution against nanoparticle toxicity and loss of reactivity due to ionic release. To recapitulate, these findings are imperative in building a sustainable framework for environmental remediation application.

Polymer-Metal Bilayer with Alkoxy Groups for Antibacterial Improvement.

Many bio-applicable materials, medical devices, and prosthetics combine both polymer and metal components to benefit from their complementary properties. This goal is normally achieved by their mechanical bonding or casting only. Here, we report an alternative easy method for the chemical grafting of a polymer on the surfaces of a metal or metal alloys using alkoxy amine salt as a coupling agent. The surface morphology of the created composites was studied by various microscopy methods, and their surface area and porosity were determined by adsorption/desorption nitrogen isotherms. The surface chemical composition was also examined by various spectroscopy techniques and electrokinetic analysis. The distribution of elements on the surface was determined, and the successful bonding of the metal/alloys on one side with the polymer on the other by alkoxy amine was confirmed. The composites show significantly increased hydrophilicity, reliable chemical stability of the bonding, even interaction with solvent for thirty cycles, and up to 95% less bacterial adhesion for the modified samples in comparison with pristine samples, i.e., characteristics that are promising for their application in the biomedical field, such as for implants, prosthetics, etc. All this uses universal, two-step procedures with minimal use of energy and the possibility of production on a mass scale.

Electromechanical Coupling Model for Ionic Liquid Gel Soft Actuators

A soft robot is composed of soft materials, which exhibit continuous deformation and driving structure integration and can arbitrarily change shapes and sizes over wide ranges. It shows strong adaptability to unstructured environments and has broad application prospects in military reconnaissance, medical rescues, agricultural production, etc. Soft robots based on ionic electroactive polymers (EAPs) have low-driving voltages, large-actuation displacements, fast responses, light weights, and low powers and have become a hot research field of bionic robots. Ionic liquid gels (ILGs) are new ionic EAPs. In this study, a new soft actuator was designed based on an ILG, and the electromechanical coupling model of an ILG soft actuator was studied in detail. Based on the system transfer function method, a mechatronic coupling model for the soft actuator was developed. According to the material characteristics and current response law of the ILG-containing EAP, an equivalent circuit model was used to describe transfer of the output current and input voltage. Based on the equivalent transformer model for ionic polymer–metal composite (IPMC) actuators proposed by Claudia Bonomo, the electromechanical coupling equation and a driving equation of the ILG soft actuator were established. The least-squares method was used with the coupling model of an ILG soft actuator to identify the system parameters for the model, and the effects of the structural parameters on the end displacement and driving force of the soft actuator were analyzed.

Polymer Metallization by Cold Spray Deposition of Polyamide-Copper Composite Coatings

Cold spray metallization of polymers is a promising surface engineering technique that enables the deposition of metal coatings onto polymer substrates at low process temperatures, resulting in improved surface properties, thus enhanced functionality of the polymeric material. However, deposition of well-adhering metallic coatings without causing surface damage to the polymer substrate is still a challenge. In this work, copper-polyamide composite coatings with different copper concentrations between 30 and 75 vol.% in the starting powders were deposited on polyamide substrates using a low-pressure cold spray system with two nozzle geometries of short and long diverging sections. The spray parameters were first developed for the deposition of polyamide powder (at gas temperature of 260 °C and gas pressures ranging from 0.41 to 1.37 MPa), and then used to spray the composite powder mixtures where the polyamide particles were acting as a binder for copper particles. Inflight and impact particle characteristics (velocity and temperature) of the polyamide powder were simulated to better understand the deposition properties. Considering that the selected conditions were suboptimal for the deposition of copper particles, no surface damage was caused as no penetration of the copper particles into the polymer substrate occurred. The results show that increasing the copper content in the powder mixtures significantly improved the resulting coating uniformity and the retained copper content. In addition, the coating deposited by spraying the powder mixture with a higher copper content of 75 vol.% and using the longer nozzle yielded the highest cohesion strength. To further improve coatings cohesion, two post-spray processing methods of furnace heating and hot pressing were used, and the effect of each process on coatings properties was investigated.Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Given name: [Kintak Raymond] Last name [Yu]. Also, kindly confirm the details in the metadata are correct.The author names are now correct: Kintak Raymond given name and Yu last nameAll other details are corrects

Developing flexible QLEDs using metal oxide and polymer combination

Quantum dot light-emitting diodes (QLEDs) offer advantages including a wide color gamut, high color purity, high brightness, low turn-on voltage, and thin form for next-generation displays. This article used a unique metal oxide and polymer combination to develop a flexible QLED. CdSe/ZnS quantum dots are synthesized using the hot-injection method, which yielded successful results. To construct the QLED, PEDOT: PSS polymer is used as a hole transport layer, enabling holes to move more efficiently due to its chain structure. The electron transfer layer utilized ZnO, which has high conductivity. Incorporating PDINO as an interlayer between ZnO and QDs in the QLED design resulted in the balanced movement of electrons and holes, reducing the turn-on voltage and increasing the turn-on speed and efficiency. By using this combination, in addition to increasing the turn-on speed of the QLED, its turn-on voltage was reduced from 6 V to 2 V and the output current increased by 0.2 mA. The device is modeled using the finite element method and Scaps-1D software to study the interlayer effect of PDINO. The use of PDINO resulted in a decrease in non-radiative recombinations near the QDs and ETL interface, while slightly enhancing radiative recombination.

Electrically Reconfigurable Metasurfaces for Frequency Selective Transmission via IPMC Kirigami

AbstractMetasurface with programmable configurations has attracted tremendous attention due to their exotic abilities to manipulate electromagnetic waves. Herein, an electrically reconfigurable metasurface for frequency selective transmission is developed based on ionic polymer–metal composite (IPMC) kirigami. First, low‐voltage driven IPMC actuators with stable actuation performance are realized, and then a thermomechanical equivalent model and a numerical electromagnetic analysis model are proposed for evaluating the deformation of the IPMC actuators and predicting the electromagnetic tunable properties of the IPMC kirigami metasurfaces, respectively. Subsequently, large‐area IPMC kirigami metasurfaces are proposed and produced by using programmable nanosecond laser micro‐processing technique that endows the uniformity of the kirigami units. Finally, the electromagnetic functionalities of these IPMC kirigami metasurfaces are researched and validated by experiments and numerical simulations. Both theoretical and experimental results demonstrate that the electromagnetic transmission frequency of the fabricated IPMC kirigami metasurface with 10 × 10 units can be tuned from 19.3 to 20.8 GHz by the application of a low voltage of 3 V. Compared with the existing reconfigurable metasurfaces, the proposed IPMC kirigami metasurface demonstrates clear advantages in its compact structure, lower driving‐voltage, low‐acoustic noise, and wide working frequency range.

Effects of γ-Irradiation and Sample Aging on the AC-Electrical Properties of Epoxy/ZnO/CB Hybrid Nanocomposites

The goal of this paper is to study the effects of gamma irradiation and samples’ aging on the AC-electrical properties of hybrid epoxy resin as a function of frequency, temperature, and (zinc oxide) ZnO content (0, 0.049, 0.099, 0.149, and 0.199 wt) at 0.001 wt of conductive (carbon black) CB nanoparticles. The irradiation processes were administered at room temperature in a gamma chamber utilizing a Cobalt 60 source of average energy = 1.25 MeV with doses = 100, 750, and 1000 Gy. The AC-electrical properties, including the impedance, dielectric constant, dielectric loss, conductivity, and activation energy of the nanocomposites, were initially studied after years of sample preparations. The collected empirical data were later analyzed before and after the gamma irradiation. The results showed that exposing samples to different doses of gamma radiation affects these AC-electrical properties significantly. It was found that the energy gap decreased as the dosage of gamma radiation increased. This could be explained as the gamma-irradiation processes induce changes in the structure of the epoxy hybrid nanocomposites by reinforcing the metal–polymer bonding and hence, causing the release of more free electrons inside the hybrid nanocomposites. Moreover, the sample aging results showed that the AC-electrical conductivity decreased with time for all samples. Hence, this study demonstrated why the γ-irradiation technique can be considered a powerful way to treat, recover, and/or enhance the electrical features of the tested epoxy hybrid nanocomposites.

Unique Possibilities of Dynamic Metal–Polymer Interactions in Selective Hydrogenation

AbstractRationally designed polymers can function as supports or promoters for metal catalysts, imparting distinct catalytic properties in selective hydrogenation. With strongly metal–ligating functional groups, mobile polymer chains can spontaneously decorate the metal catalyst surfaces under mild conditions, forming stable metal–polymer interfaces. We have termed this phenomenon ‘dynamic metal–polymer interaction (DMPI),’ which can be roughly considered as an organic version of the strong metal–support interaction (SMSI) concept. The polymer chains that dynamically interact with the metal surface can control the adsorption of reactants and products through competitive adsorption, significantly improving selectivity and catalyst stability. One of the remarkable advantages of using polymers as catalytic materials is that their molecular structures, such as molecular weight, crystallinity, and chemical functionality, can be tailored using rich organic chemistry. This, in turn, allows us to precisely tune the metal–polymer interactions and catalytic properties. In this Concept, we will discuss how metal–polymer interfaces can be designed and utilized for selective hydrogenation, with a particular emphasis on the industrially relevant acetylene partial hydrogenation reaction.

A review on key factors influencing the electrical conductivity of proton exchange membrane fuel cell composite bipolar plates

AbstractFuel cells are gaining increasing importance as a promising alternative to traditional energy sources, primarily due to their exceptional efficiency and environmental advantages. The electrical performance of proton exchange membrane fuel cells (PEMFCs) largely depends on the effectiveness of proton and electron transport within the cell components. A critical factor impacting this efficiency is the electrical conductivity of polymer‐based bipolar plates (BPPs), which play a fundamental role as current collectors. BPPs in PEMFCs can be made from various materials including coated metallic materials, graphitic materials, and polymer composites. This review exclusively concentrates on polymer composite BPPs. Enhancing the overall cell performance is achievable through the integration of electrically conductive additives into the polymer matrix of these plates. Graphite (GR), carbon black (CB), carbon fibers (CF), carbon nanotubes (CNT), and graphene (Gr) all emerge as highly promising functional materials capable of substantially elevating BPPs performance. This study, among its various objectives, delves into the synergistic effects of these electrically conductive additives and their capacity to enhance the electrical conductivity within polymeric matrices. Furthermore, this review article thoroughly explores the influence of the polymeric matrix, encompassing co‐continuous morphology and processing conditions. In essence, it focuses on the improvement of BPPs electrical conductivity through innovative designs of their polymer‐based composites and nanocomposites and the particular selection of the electrically conductive fillers. The insights derived from this study significantly contribute to a more profound understanding of how to effectively harness the potential of this vital PEMFC component.

Kirigami-inspired self-powered pressure sensor based on shape fixation treatment in IPMC material

Rapid advances in sensing technologies have brought about the fast development of wearable electronics for biomedical applications. Since its conception, over the years, the ionic polymer metal composite (IPMC) is a new man-made material that has demonstrated its great potential for wearable devices due to self-powered sensing capabilities. Here, for the first time, a novel Kirigami technique with unique cut patterns has been employed for designing a stretchable IPMC sensor with enhanced performance. As Nafion itself exhibits the characteristic of shape memory polymer, the Kirigami structure that is built using the IPMC can be buckled up by loading and heating the IPMC above the deformation temperature, T def. To further enhance the memory effect, the Kirigami structure has further been locked by immersing it in potassium hydroxide for the formation of deprotonated Nafion. The voltage output of the proposed IPMC with Kirigami shows a superior performance with 3 times improvement over the conventionally planar electrodes. Dynamic tests with a range of displacements have been performed to validate the sensor design and the robustness of the Kirigami structure. This novel Kirigami-based IPMC sensor has been successfully demonstrated for braille sensing by designing 7 independent electrodes.

Evolution of coupling modes between α and β relaxations in metallic glass-forming liquids revealed by nano-calorimetry

The coupling behavior of α and β relaxations in supercooled liquids (SLs) is a key scientific issue that relates to the essence of glass transition and the modulation of glass properties. Here, we observe the evolution of α and β relaxations in Au50Ag7.5Cu17.5Si25 alloys from glass to SLs by nano calorimetric technique. We find that all the β participates in α relaxation in these metallic glasses (MGs) upon heating. Two typical coupling (or decoupling upon cooling) modes of α and β relaxations in Au-based MG SLs have been discovered, dependent on the degree of coupling between α and β relaxations in glasses. The coupling degree increases during the isothermal annealing process as the energy state of the glass decreases. Above a critical degree the decoupling mode changes from “β splits from α” to “α splits from β”. A survey including metallic glasses, polymer glasses and oxide glasses shows the general existence of the critical degree of coupling in glasses. The differences in local structure feature in glasses with different coupling degree is elucidated by analysis on atomic nonaffine displacements using molecular dynamics simulations. Further our work demonstrates that the plasticity of MGs can be effectively modulated by altering the coupling behavior between α and β relaxation.

Plasma Technology Applications in Proton Exchange Membrane Fuel Cell Systems

AbstractFuel cells have become a prominent research focus in the realm of clean energy, owing to their attributes of environmental sustainability, high efficiency, and renewable potential. The catalytic activity of electrode materials and the characteristics of proton exchange membranes are considered pivotal determinants of fuel cell performance. Plasma is abundant in high‐energy electrons and active species, proven to be a rapid, facile, and green approach for the preparation and treatment of catalytic materials and polymers. This review presents recent applications of plasma technology in proton exchange membrane fuel cells across four key dimensions: cathodes, anodes, proton exchange membranes, and process enhancement, including the preparation and treatment of noble metal catalysts, non‐noble metal catalysts, non‐metal catalysts, and polymer membranes. Furthermore, critical issues of plasma technology applied in PEMFCs were also discussed.

Polymeric Metal Halides with Bright Luminescence and Versatile Processability

AbstractMost of current metal halide materials, including all inorganic and organic–inorganic hybrids, are crystalline materials with poor workability and plasticity that limit their application scope. Here, we develop a novel class of materials termed polymeric metal halides (PMHs) through introducing polycations into antimony‐based metal halide materials as A‐site cations. A series of PMHs with orange‐yellow broadband emission and large Stokes shift originating from inorganic self‐trapped excitons are successfully prepared, which meanwhile exhibit the excellent processability and formability of polymers. The versatility of these PMHs is manifested as the broad choices of polycations, the ready extension to manganese‐ and copper‐based halides, and the tolerance to molar ratios between polycations and metal halides in the formation of PMHs. The merger of polymer chemistry and inorganic chemistry thus provides a novel generic platform for the development of metal halide functional materials.

Polymeric Metal Halides with Bright Luminescence and Versatile Processability.

Most of current metal halide materials, including all inorganic and organic-inorganic hybrids, are crystalline materials with poor workability and plasticity that limit their application scope. Here, we develop a novel class of materials termed polymeric metal halides (PMHs) through introducing polycations into antimony-based metal halide materials as A-site cations. A series of PMHs with orange-yellow broadband emission and large Stokes shift originating from inorganic self-trapped excitons are successfully prepared, which meanwhile exhibit the excellent processability and formability of polymers. The versatility of these PMHs is manifested as the broad choices of polycations, the ready extension to manganese- and copper-based halides, and the tolerance to molar ratios between polycations and metal halides in the formation of PMHs. The merger of polymer chemistry and inorganic chemistry thus provides a novel generic platform for the development of metal halide functional materials.

Spectral Functions of Metallic Fullerene Polymers: A Theoretical Tool for Atomic Structures Identification

Spectral Functions of Metallic Fullerene Polymers: A Theoretical Tool for Atomic Structures Identification

The copolymerized sulfur coordination-metal complex dye sensitizer exhibiting the highest power conversion efficiency (PCE) 11.78% in dye sensitized solar cells

Polymeric metal complex dyes have been recognized as a significant class of dye sensitizer for optoelectronic applications due to their unique properties. In order to improve the light absorption and photovoltaic performance and to decrease costs, five novel D-A-π-A motif copolymerized sulfur coordination-metal complexes (BDTT-BBT-Ni, BDTT-BBT-Cu, BDTT-BBT-Zn, BDTT-BBT-Cd and BDTT-BBT-Hg) have been designed and synthesized for being used as dye sensitizer. And the photovolataic performance test results show that the highest PCE of the copolymer complex BDTT-BBT-Hg of five copolymers has reached 11.78% and the copolymer dye sensitizers are simple and inexpensive to synthesize and have good solubility. These results provide a new way to develop stable and efficient metal complexes with sulfur coordination dye sensitizers in the future.

Preventing partial discharge in liquid metal polymer composites under steep voltage pulses

Liquid metal polymer composites (LMPCs) offer viable solutions for deformable electronics, including sensors and actuators. To ensure the longevity of the deformable technologies, partial discharge (PD) must be mitigated as it causes premature material aging and device failure. While studies on the dielectric properties of LMPCs have mainly focused on AC voltage, a large number of deformable applications will inevitably involve power electronics for higher efficiency and power density. Consequently, addressing PD in LMPCs under repetitive steep voltage pulses generated by power electronic switches becomes important. This study employs an electric field cancellation technique using electrets to reduce the PD magnitude and increase the partial discharge inception voltage (PDIV) of LMPCs under steep square voltage waves. We placed either a non-electret or electret thin film on top of LMPC samples and conducted PD experiments in flat and bent test coupon arrangements. The results show that electrets can reduce PD magnitude and increase PDIV in both test arrangements. Furthermore, the study provides deeper insights into the experimental results by conducting the electric field analysis of the LMPC experiments through numerical models.

INVESTIGATION OF THE INFLUENCE OF SUPERPOSITION OF HIGH-FREQUENCY VIBRATIONS DURING THE CURING OF A METAL POLYMER ON ITS STRUCTURE

The article provides a description and results of an experimental study on the compaction of a metal-polymer material under the action of ultrasound, which is supposed to be used as a reinforcing component of various composite engineering systems. The scheme of the experiment and the used equipment and materials, measuring equipment are given. A brief mathematical analysis of the dynamics of a viscous fluid flow and the laws describing these processes is presented. A hypothesis has been formulated about an increase in the density of the metal polymer under the action of ultrasound, due to the introduction of additional vibration energy and its dissipation in the metal polymer, which should lead to a decrease in viscosity. The obtained metal-polymer samples were examined visually and using a durometer, the results are presented as images of samples sections and tabular data. Based on the data obtained, a histogram of the dependence of hardness and the number of gas pores on the time of ultrasonic exposure was constructed. In conclusion, an analysis of the obtained data is given, and conclusions are drawn about the effect of using ultrasound during pouring and curing of a viscous metal polymer. New directions for studying the effect of low-frequency vibrations on the viscosity of the metal-polymer composition are proposed in order to create technological equipment for the implementation of the technology for creating composite machine-building systems based on metal-polymer.

Эффективность применения антифрикционных твердосмазочных покрытий для пар трения «металл– полимер»

Эффективность применения антифрикционных твердосмазочных покрытий для пар трения «металл– полимер»

Influence of bromination arrangement and level on the formation of polybrominated dibenzo-p-dioxins and dibenzofurans from pyrolysis and combustion of polybrominated diphenyl ethers: Mechanisms and kinetics

Controlling the emission of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) presents a huge challenge in the thermo-chemical conversion of halogenated waste. It is crucial to understand the formation of PBDD/Fs to effectively control their emissions. This paper utilizes density functional theory calculations to comprehensively explore the mechanisms and kinetics of PBDD/Fs formation using 65 polybrominated diphenyl ethers (PBDEs) with varying bromination arrangements and levels. The study uncovers two new pathways for the formation of PBDFs from PBDEs, i.e., two-step H2 elimination and ether-ketone isomerization at ortho-C(H) sites. These pathways are applicable to PBDEs with specific bromination arrangements. In the case of some PBDEs, their initial energy barriers are comparable to the generally accepted direct HBr elimination. It is found that low-brominated PBDEs have a higher risk of forming PBDD/Fs, while high-brominated PBDEs are more likely to break ether bonds and generate polybromobenzenes. The study also investigates the effects of polymer materials and metals on the formation of PBDD/Fs from PBDEs to explain the high yield of PBDD/Fs in the co-treatment of PBDEs with polymers and metals. The involvement of polymers and metals significantly reduces the energy barriers for the formation of PBDD/F precursors, namely ortho-phenyl-type radicals, accelerating the formation of PBDD/Fs. This study markedly advances the present understanding of the transformation of PBDEs into PBDD/Fs and provides theoretical guidance for reducing pollutant emissions in the thermal treatment and cleaner conversion of PBDE-containing waste.